Chapter 15 - Mechanisms of Attention

Abstract

This chapter reviews some of the studies demonstrating that attention is associated with an increase in activity in the brain region concerned with the processing of whatever it is that is being attended to. The basic assumption is that there is competition between stimuli for processing by the nervous system. The stimulus that wins this competition elicits more neural activity and becomes the focus of attention. Furthermore, chapter discusses the biased competition model, which states that a stimulus gains attention by winning a competition with other stimuli. The biased competition model has provided a very useful framework for guiding neuroimaging studies of selective attention in many different laboratories. However, the biased competition model is underspecified. It states that there are bottom-up processes that determine which stimulus will win the competition for attention, but it does not say anything about the intrinsic properties of the stimulus that wins. The model states that there is a top-down biasing signal that modifies the competition, but it does not say anything about the nature of this top-down signal. The last section of this chapter makes some suggestions that go slightly beyond the biased competition model.